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Biomedical subjects

T Sauer

Publications and source records attributed to T Sauer.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Determination of estrogen receptors in aspirates from needle biopsies of breast carcinomas. Correlation to a biochemical method].

Several methods exist for determining oestrogen receptor status in breast carcinomas. Biochemical methods have been widely used for many years, but recently immunocytochemical methods have become available. We have compared the outcome of the biochemical and immunocytological analysis in 274 breast cancer patients. Fine needle aspirates from all the patients were investigated immunocytologically and 214 tumours were positive (78%) and 60 negative (22%). Biochemical data were available in 155 patients, and the concordance between the two methods was 88%. Most of the 119 carcinomas (43%) that were only investigated cytologically were too small to allow both histological and biochemical analysis. A minority of patients were not operated on because of high age, and/or impaired health, or because the tumour was inoperable. In our opinion, biochemical and immunocytological methods are equally sensitive and specific in detecting oestrogen receptor in breast tumour tissue. In fine needle aspirates there is the additional advantage of morphological assessment of malignant nuclei and the possibility of obtaining material from small lesions.

Biopsy, Needle↗
PubMed1994

Expression of the pS2 protein and correlation with estrogen receptor status in fine-needle aspirates from breast carcinomas.

A series of 36 cases of breast carcinomas diagnosed by fine-needle aspiration were investigated for the presence of estrogen receptors (ER) and the estrogen-induced pS2 protein. Immunocytochemically ER could be demonstrated in 28 aspirates, whereas eight were negative. These eight were also negative for the pS2 protein. In addition three aspirates with a low score for ER and five with a high score for ER were found negative for pS2. Thus, of the 36 cases, 20 were found to express the pS2 protein. The presence of the pS2 protein in the tumor cells is believed to be a marker of a functional estrogen regulatory system and its demonstration may therefore predict clinical responsiveness to hormonal therapy.

Biopsy, Needle↗
PubMed1994

Stochastic versus deterministic variability in simple neuronal circuits: I. Monosynaptic spinal cord reflexes.

Long time series of monosynaptic Ia-afferent to alpha-motoneuron reflexes were recorded in the L7 or S1 ventral roots in the cat. Time series were collected before and after spinalization at T13 during constant amplitude stimulations of group Ia muscle afferents in the triceps surae muscle nerves. Using autocorrelation to analyze the linear correlation in the time series demonstrated oscillations in the decerebrate state (4/4) that were eliminated after spinalization (5/5). Three tests for determinism were applied to these series: 1) local flow, 2) local dispersion, and 3) nonlinear prediction. These algorithms were validated with time series generated from known deterministic equations. For each experimental and theoretical time series used, matched time-series of stochastic surrogate data were generated to serve as mathematical and statistical controls. Two of the time series collected in the decerebrate state (2/4) demonstrated evidence for deterministic structure. This structure could not be accounted for by the autocorrelation in the data, and was abolished following spinalization. None of the time series collected in the spinalized state (0/5) demonstrated evidence of determinism. Although monosynaptic reflex variability is generally stochastic in the spinalized state, this simple driven system may display deterministic behavior in the decerebrate state.

Afferent Pathways↗
PubMed1994

Stochastic versus deterministic variability in simple neuronal circuits: II. Hippocampal slice.

Long time series of Schaffer collateral to CA1 pyramidal cell presynaptic volleys (stratum radiatum) and population spikes (stratum pyramidale) were evoked (driven) in rat hippocampal slices. From the driven CA1 region in normal [K+] perfusate, both population spike amplitude and an input-output function consisting of population spike amplitude divided by the presynaptic volley amplitude were analyzed. Raising [K+] in the perfusion medium to 8.5 mM, slices were induced to spontaneously burst fire in CA3 and long time series of inter-burst intervals were recorded. Three tests for determinism were applied to these series: a discrete adaptation of a local flow approach, a local dispersion approach, and nonlinear prediction. Surrogate data were generated to serve as mathematical and statistical controls. All of the population spike (6/6) and input-output (6/6) time series from the normal [K+] driven circuitry were stochastic by all three methods. Although most of the time series (5/6) from the autonomously bursting high [K+] state failed to demonstrate evidence of determinism, one (1/6) of these time series did demonstrate significant determinism. This single instance of predictability could not be accounted for by the linear correlation in these data.

Algorithms↗
PubMed1994

Influence of fractionation schedule on development of intestinal complications following localized irradiation. An experimental study in the rat.

This study examined the relationship among time-dose-fractionation, development of intestinal complications, and histopathologic radiation injury in rat small bowel. In 177 rats, a functional loop of rat ileum was surgically transposed to the left scrotum. Three weeks later, fractionated irradiation was delivered to the transposed intestine as 2.8 Gy or 5.6 Gy daily fractions, or as 2.8 Gy twice daily with 12 hours' interval. Eleven experimental groups received total doses ranging from 28 Gy to 90 Gy. The animals were observed for intestinal complications, and groups of animals were killed 2 and 26 weeks after completion of irradiation for assessment of injury. Radiation injury was assessed by a semiquantitative histopathologic scoring system and by the frequency of lethal intestinal complications. Both increased fraction size and reduced overall treatment time increased the severity of subacute and chronic radiation injury, as well as frequency of intestinal complications. We conclude that rapidly proliferating cells (mucosal epithelium) play a pivotal role in the pathogenesis of radiation enteropathy and mechanisms other than radiation-induced mitotic cell death are pathogenetically involved.

Animals↗
PubMed1993

[Puncture cytology in tumors of the head and neck region].

In a series of fine needle aspirations performed in 541 patients with visible and/or palpable lesions in the head and neck, histological results were available in 205 the of cases. The cytological and histological diagnoses were compared. In three of the 205 cases the smears were inadequate for diagnosis. Discrepancies were noted in 18 cases (8.7%), and ten false negatives (specificity 91.2) and eight false positives (sensitivity 92.5). The main diagnostic problem was to differentiate between malignant lymphoma and benign lymphadenopathy. Biopsy is therefore recommended when malignant lymphoma is suspected. In this series both the aspirations and the subsequent evaluation of the smears were carried out by a cytopathologist. We conclude that this model increases the accuracy and reliability of fine needle aspiration in head and neck tumours by reducing the number of non-representative smears.

Biopsy, Needle↗
PubMed1992

Immediate interpretation of FNA smears from the head and neck region.

FNA smears from 540 patients, investigated for visible and/or palpable lesions in the head and neck, examined immediately during consultation have been compared with the final cytologic diagnoses and, when possible, with histologic results. Preliminary and final cytologic diagnoses differed in 25 cases (4.6%). Major discrepancies as to whether a lesion was benign or malignant occurred in 15 cases (2.8%). Histologic follow-up was available for 188 lesions (35%). There were 5 false-positive (2.6%) and 9 false-negative (4.7%) diagnoses, giving a sensitivity of 90.6% and a specificity of 94.6%. The main diagnostic problem was benign, reactive lymphadenitis versus malignant lymphoma, which was responsible for 11 of 14 erroneous cytologic diagnoses (3 false-positive and 8 false-negative smears).

Biopsy, Needle↗
PubMed1992

Tolerance of rat small intestine to localized single dose and fractionated irradiation.

The tolerance of rat small intestine to localized single-dose and fractionated irradiation was assessed. In 168 rats, bilateral orchiectomy was performed and a loop of small intestine was transposed to the left part of the scrotum. Beginning 3 weeks postoperatively, single dose (18-24 Gy) or fractionated (4.2 Gy or 5.6 Gy per fraction) x-irradiation was delivered to the transposed intestine. The animals were observed for complications, and groups of animals were killed 2 and 26 weeks after completion of irradiation for assessment of injury. Mortality (i.e. the occurrence of lethal intestinal complications) and a semiquantitative histopathologic scoring system were used as endpoints to assess the degree of radiation injury. The most frequent intestinal complications were enterocutaneous fistula formation and intestinal obstruction. Logistic regression analysis ov complications data was used to estimate LD50 values and the alpha/beta ratio. There was good correlation between histopathologic scores and the incidence of lethal complications. The estimated LD50 values were 22.1 +/- 0.5 Gy, 37.0 +/- 4.4 Gy and 51.0 +/- 5.3 Gy for the single dose regimen and the fractionated regimens of 5.6 Gy and 4.2 Gy respectively. The estimated alpha/beta ratio was 10.7 +/- 2.4 Gy. The goodness of fit of the linear-quadratic isoeffect model to our data was satisfactory. Our results indicate that acute mucosal damage may be pathogenetically involved in the development of intestinal complications.

Animals↗
PubMed1992

[Not Available].

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Germany↗
PubMed1991

The portal bifurcation and the termination of the hepatic veins: an anatomical investigation into the projection of the ultrasonographically important hepatic vessels onto the anterior body wall.

An investigation was carried out on 50 cadavers, in which the projection onto the anterior abdominal wall of the following vascular points was examined: the portal bifurcation, the direction of the course of the right and left branches of the portal vein and the terminal course of the hepatic veins near their entry into the inferior vena cava (IVC). The results are related to a transverse axis passing through the apex of the xiphoid process and the median plane in the supine position. The average position of the portal bifurcation is projected onto a point between a vertical line passing through the midpoint of the right hemithoracic width and a horizontal line passing through a point on the midclavicular line (MCL) corresponding to 57% of the height of the liver measured upwards from its inferior margin. The axis of the prehepatic course of the portal vein makes an angle of about 50 degrees, open downwards, with a vertical line drawn through the apex of the internal angle of the portal bifurcation. A line parallel to the course of the right and left branches of the portal vein is projected on to a surface line cranial to the right costochondral margin, which runs upwards at an angle of approximately 20 degrees towards the apex of the xiphoid process. The termination of the three great hepatic veins is projected at about the level of the xiphisternal joint, one sternal width to the right of the midline. Close to the IVC, the right hepatic vein runs upwards and medially at an angle of between 20 degrees and 30 degrees with the transverse plane.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Mucosal surface area of a reversed intestinal segment in rats.

Only scarce knowledge exists of morphologic changes after antiperistaltic reversal of the small intestine. Previous animal models using a reversed segment of the small intestine after massive intestinal resection have been mostly concerned with assessing absorption. A rat model was therefore developed for the purpose of studying mucosal surface area in the small intestine after reversal of an intestinal segment. A reversal of 10 cm, representing a length of about 10%, was found suitable for the investigation. Marked dilatation of the reversed segment occurred. A pronounced increase in mucosal surface area caused by mucosal hyperplasia was observed. The mucosal surface area in an anastomosed, but not reversed, segment also increased markedly compared with a group undergoing no operation, although less than in the reversed segment. We conclude that a reversed intestinal segment will increase mucosal surface area in an optimal length used for this purpose. This increase is possibly caused by prolonged exposure to intestinal chyme.

Animals↗
PubMed1991

[Not Available].

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Education, Medical↗
PubMed1990

[Expanded trans-pedicular spongiosa grafting--dorsal approach to filling of the intervertebral spaces with cancellous bone].

Internal fixation of dorsolumbar spinal fractures can be accomplished by dorsal plating or internal fixator. So far, the technique of transpedicular grafting has been applied to fill the vertebral body with cancellous bone. In this paper, we present a new technique of extended transpedicular bone grafting to fill the intervertebral space also. By this means, the disadvantage of secondary loss of height after removal of the metal implants can be prevented.

Bone Plates↗